Hydraulic system



Jan., 23 WM H. HERMANNY 2,539,134

HYDRAULIC SYSTEM Original Filed March l2, 1945 Heinrich Irmcuzizy.

Patented Jan.. 23, 1951 HYDRAULIC SYSTEM Heinrich Hermanny, Valley Stream, N. Y., assigner to Bendix Aviation Corporation, Norwood, Mass., a corporation f Delaware Original application March 12, 1943, Serial No. 478,989, now Patent No. 2,396,653, dated March 19, 1946. Divided and this application March 1, 1946, Serial No. 651,137

2 Claims. (Cl. 13S-26) This invention relates to hydraulic systems,

and particularly to the control of pressure surges to prevent damage to parts of such a system.

An object ci the invention is to provide a novel method and means of absorbing a suddenly applied pressure impulse of abnormally great magnitude, such as might result from an explosion under the surface of a body of water in which is located a vessel such as a ship or submarine carrying susceptible parts of a hydraulic system.

rIhe invention is herein illustrated as applied to the protection of a hydraulic circuit which includes a bellows assembly of a character ernployed in marine measuring apparatus; but it is to be understood that the invention has broader application and that its scope is deined by the appended claims rather than by the illustrated exemplification thereof.

In the drawings:

Figure 1 shows the invention applied to the protection of a bellows assembly, as above noted;

Figure 2 is a more detailed showing of one of the control units oi Figure 1; and

Figure 3 is a more detailed showing of another of the control units of Figure l.

As shown, the illustrated embodiment is applied to a bellows assembly t, divided (by a diaphragm l) into two chambers, 8 and 9, the former receiving the pressure ('Pitot) conduit Il and the latter receiving the static conduit l2; the index actuating rod I3 being attached to the diaphragm 'i for operation of any associated measuring or other apparatus (as in Rydberg Patent No. 1,968,539, for example). The inner spaces i6 and il are exposed to the pressure of the atmosphere surrounding the unit E, as is customary.

Numeral i8 designates a -rodmeter, as it is termed in the art, having terminal openings E9 and 29 for the conduits ll and l2, respectively; the said rodmeter I8 being attached to the hull oi the vessel, so that openings i9 and 20 are exposed to the open sea, as are openings 3 and 5 in Figure l of the Rydberg patent, above identied. Numerals 2l and 22 designate automatic Valve assemblies, and valves 23 and 2A are provided to permit temporary by-passing of the Valves 2l and 22, respectively, during conditioning and servicing.

Air collectors 2e and 2l are provided in the lines Il and l2, respectively; each air collector including a tube (as at 35) projecting externally and adapted to be vented to atmosphere, when desired, by opening of vent valve 3l or 92, as the case may be, and projecting internally sufficiently to insure the trapping of a quantity of air at all times. These air collectors are claimed herein, per se, whereas the system as a whole is claimed in my parent application No. 478,989,

filed March l2, 1943, and issued March 19, 1946, as Patent 2,396,553 oi which this application is a division.

Operation lf the pressure increases suddenly due to the explosion of a depth charge, the entrapped air in collectors 2t and 2? is compressed by the inrush of water through the snubber valves 2| and 22. The piston d! of each valve rises and closes off its upper orice, thus blocking the further passage of water before the pressure applied has increased sufiiciently to injure the bellows assembly t. As soon as the pressure subsides, the pistons will drop due to gravity and the system will again be safe for normal operation.

Also, as the pressure subsides, the trapped air in the collectors expands to re-occupy all the space between the top of the collectors and the bases of the tubes 39, thus restoring the air cushions to their normal volumes, the said normal volume being determined by fixing the tubes 36 with their ends at a predetermined distance below the tops oi the respective collectors. This distance is pre-set, that is, an initial adjustment is made, depending upon the amount of liquid which is to be permitted to ow through the snubber valves il for a given pressure difference. Likewise an initial adjustment is made of the distance between each snubber orice and its valve to predetermine the time required ,to effectively block the passage. These values can be determined experimentally and the adjustments made accordingly. Once made, they remain fixed and constant during the ensuing period or" operation of the system.

During rough weather air bubbles will infiltrate through the rod meter and accumulate in the air collectors 29 and 2l. The air cushions will therefore increase in volume and must be corrected from time to time by opening the valves 3l and 3,2 to blow oli the excess. It is common practice to open the valves 3l and 32, and the bypass valves 23 and 2s once every four hours.

What is claimed is:

1. Hydraulic cushioning mechanism comprising a vessel adapted to contain a predetermined level of liquid therein and to contain a predetermined volume of air above said level, and having an opening below said level to receive liquid 3 4 containing air, air vent means adjacent the top UNITED STATES PATENTS of said Vessel and including a passage communi- Number Name Date eating with the interior of said vessel at said prel 035 386 Prescott et aL Aug. 13 1912 determined level, said passage limiting the air 21321093 Lupfer June 8 1943 venting action and thus insuring retention of 5 214161025 Snai lFeb 18 1947 an air-cushion of said predetermined volume at 2,417,256 Kremmer Mar. 11i 1947 the end of a venting operation.

2. Apparatus according to claim 10 in which FOREIGN PATENTS said air vent means includes a valve for selec- Number Country Date tively shutting 01T fluid OW through Said pS- 10 484,930 France Mar. 24, 1917 sage. 56,634 Austria Aug. 1912 HEINRICH HERMANNY. 655,775 Germany Apr. 16, 1935 REFERENCES CITED The following references are of record in the 15 le of this patent: 

